Wirelaying tool

ABSTRACT

A wirelaying apparatus and method using a tool ( 30 ) having a cutter/cutting tip ( 31 ) operatively opening a cut in the interior bore surface ( 11 ) of a cylindrical pipe fitting ( 10 ), laying wire ( 12 ) into the cut and closing the cut using a flange closer ( 33 ). The wire ( 12 ) is delivered into the cut via an aperture ( 32 ) through the cutting tip ( 31 ). Delivery of the wire ( 12 ) into the cut is thereby improved, overcoming the problem of wire running free within the fitting. In a second embodiment (see FIG.  12 ) the cutter ( 31 ) is rotatably mounted allowing a double helical coil to be formed without removing the cutter from the bore surface.

This application is a continuation-in-part of application Ser. No. 10/300,075, filed on Nov. 20, 2002 now U.S. Pat. No. 6,751,840. The present invention relates in general to an apparatus and method for laying wire, and in particular but not exclusively to a tool for laying wire into the surface of a body. In a preferred embodiment, the invention relates to a method and apparatus for laying wire into an interior bore-surface of a pipe fitting.

Pipe fittings are commonly used to couple the ends of pipes including, for example, plastics material gas supply pipes. Such pipes must be connected by a sealed joint so that, in use, no gas is permitted to escape through the joint.

One known method of making such a sealed joint is to engage the ends of the plastic pipes to be joined in a pipe fitting in the form of a cylindrical sleeve. An electrical conductor is embedded in an inner bore-surface of the sleeve, usually in the form of a helical coil of copper wire. When an end of each pipe is positioned in the sleeve, an electrical current is passed through the wire causing the wire to become heated, thereby melting the plastics material on the bore-surface of the sleeve or on the exterior surfaces of the pipes, or both. The end of the pipe thereby becomes fused or welded to the sleeve in a gas-tight sealed joint.

EP-A-O, 569,625 discloses a prior art apparatus for 30 laying wire into the interior bore surface of a pipe fitting, comprising a cutting tool for cutting a groove in the interior surface, a wire guide for guiding wire into the groove, and an enclosing means for returning the cut material back into the groove to enclose the wire.

A problem arises with the prior art apparatus and method in that a separate tool is required for each diameter of pipe fitting, because the shape of the prior art tool closely follows the internal diameter of the pipe fitting. When the wire laying tool is used on an inappropriate size of sleeve, the wire is not correctly laid into the groove and instead tends to run free inside the fitting, rendering the fitting useless.

It is desired to improve the flexibility and reliability of the prior art method and apparatus. Also, in at least a first preferred embodiment, it is desired to provide a method and apparatus for laying wire into a body having a non-constant internal diameter. That is, an internal diameter that varies along all or part of the length of the body, such as a reducer pipe fitting.

Further, it is desired to provide a method and apparatus for laying wire into a body having a non-useable area, such as a side aperture of a T-shaped pipe fitting. It is desired to lay a single wire along a T-shaped pipe fitting in a helical coil at and near first and second ends thereof but avoiding the side aperture.

Further still, in another preferred embodiment, it is desired to provide an improved method and apparatus for laying a double helical coil of a single piece of wire such that the wire returns to near a starting point.

According to the present invention there is provided an apparatus and method as set forth in the appended claims. Preferred features of the invention will be apparent from the dependent claims, and the description which follows.

According to a first aspect of the present invention there is provided wirelaying tool for laying wire into an interior bore surface of a hollow cylinder, comprising: a cutting tip for, in use, making a cut into an interior bore surface of a hollow cylinder; a wire guide aperture for guiding wire into the cut, the wire guide aperture extending through the cutting tip to an exterior surface of the cutting tip lying in the cut in use such that the wire enters the cut directly through the cutting tip; and an encloser for closing the cut after the wire has been fed into the cut, thereby enclosing the wire in the cut.

Advantageously, the wire enters the cut directly 20 through the cutting tip and therefore cannot run free. Preferably, the wire is guided through an aperture in the cutting tip ideally to an exterior surface of the cutting means that, in use, faces into the cut.

Preferably, the cutting tip is arranged to produce a cut which is substantially normal to said interior bore surface, and in the form of a groove. In one embodiment, the cutting tip preferably lifts a flange to one side of the cut. Ideally, the wide guide aperture guides the wire into the cut to an area underneath the flange, and preferably a corner position underneath the flange.

Preferably, said cutting tip, said wire guide and said encloser of the wirelaying tool are integrally formed. Preferably, said tool is arranged to be carried on an elongate bar, with said wire preferably being fed along the bar, suitably by a wire delivery means such as pulley arrangement, to said wire guide.

The preferred embodiment is particularly intended for laying wire into the interior bore surface of a plastics material pipe or pipe fitting. A wirelaying apparatus is preferably arranged to receive said pipe or pipe fitting for rotation about a longitudinal axis thereof with said wirelaying tool being held on the elongate bar against said interior bore surface such that the pipe fitting is operatively rotated with respect to the wirelaying tool.

Preferably, the wirelaying tool is arranged such that the enclosing means is in a plane normal to the longitudinal rotational axis of the pipe fitting. Therefore, maximum pressure may be applied by the enclosing means to close the flap cut by the cutting means even if the tool is used with a pipe fitting having an internal diameter substantially greater than the exterior circumference of the tool. However, the wirelaying tool is preferably arranged to have an exterior circumference corresponding to the interior diameter of an intended pipe fitting.

Preferably, the wirelaying tool is mounted into a 30 receiving recess in said bar such that said tool is carried aligned with an end face and an outer circumferential face of the bar. By mounting the wirelaying tool in this position on the bar, several operational advantages are achieved. In particular, the cutting means is arranged to lie at or near the end of the bar. Placing the cutting tool in this position allows the cutting tool to remain in contact with the interior bore surface even if the internal diameter of the bore surface changes along the length of the pipe fitting, such as in a reducer used to couple pipes of different diameters.

A further advantage of the wirelaying apparatus is that 10 the pitch of the helical path followed by the wirelaying tool may be changed during wirelaying. In particular, the wirelaying apparatus may move the wirelaying tool to greatly increase the pitch of the helical path. This feature is particularly advantageous, for example, in laying a continuous piece of wire within a T-shaped pipe fitting such that the wire may be laid to avoid a side aperture of the T-shaped fitting.

According to a second aspect of the present invention 20 there is provided a wirelaying apparatus, for laying wire into a body, said apparatus comprising a cutting means that is rotatable about an axis substantially normal to an interior bore surface of said body.

The cutting means is preferably provided with a cutting face preferably intended for making a cut, in use, by moving said cutting means through said interior bore surface, in the direction of said cutting face. Advantageously, said cutting means is rotatable, such that said cutting face is rotated about said axis. Preferably, a wire guide means guides a wire through said cutting means along said axis such that said cutting means rotates about said wire.

Advantageously, the cutting tool is driven in a first direction, to lay wire in a first helical path, is then rotated through substantially 90° and driven to lay wire along a linear path, and then rotated through a further 90° to lay wire in a second helical path. Preferably, the second helical path lies between said first helical path such that a double helical path is formed.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which:

FIG. 1 is a perspective side view of a pipe fitting;

FIG. 2 is a sectional view through the pipe fitting of FIG. 1;

FIG. 3 is a plan view of a wirelaying apparatus;

FIG. 4 is an end view of a wirelaying tool in use in a pipe fitting;

FIG. 5 is a side view of the wirelaying tool;

FIG. 6 is a front view of the wirelaying tool;

FIG. 7 is a plan view of the wirelaying tool;

FIG. 8 is a sectional side view of a preferred reducer pipe fitting;

FIG. 9 is a rear elevational view of a second preferred wirelaying apparatus;

FIG. 10 is a plan view of the apparatus of FIG. 9;

FIG. 11 is an end view of the apparatus of FIG. 9;

FIG. 12 is a cross-section view through a preferred head portion of the wirelaying apparatus of FIG. 9;

FIG. 13 is a cross-sectional view through a preferred sleeve pipe fitting having a double helical wire coil laid therein;

FIG. 14 is a plan view of a wirelaying tool according to another preferred embodiment of the present invention;

FIG. 15 is an elevation view of the tool of FIG. 15;

FIG. 16 is a side view of the tool of FIGS. 14 and 15;

FIG. 17 is a partially cut-away view of a preferred 25 wirelaying tool in use;

FIG. 18 is an enlarged view of part of FIG. 17; and

FIG. 19 is a side sectional view showing the 30 preferred wirelaying tool in use.

Referring firstly to FIGS. 1 and 2, a pipe-fitting 10 is shown in the form of a sleeve used to connect the ends of pipes such as gas pipes. The fitting 10 is hollow and generally cylindrical and has an inner bore-surface 11. Embedded in the bore-surface 11 is a helical coil of copper wire 12, a first end 12 a of which protrudes from a first port 13 a on the exterior of the fitting 10 and the second end 12 b of which protrudes from a second port 13 b on the exterior of the fitting 10.

Referring also now to FIG. 2, this shows, in cross- 10 section, a portion of the bore-surface 11 of the fitting 10 with the helical coil of copper wire 12 embedded therein. The turns of the wire 12 are enclosed by the plastics material of the bore-surface 11 causing the bore-surface 11 to undulate. The wire is securely retained in the bore-surface 11 and is not prone to becoming detached, as has been the case with prior fittings of this kind.

In use, when the fitting is required to connect two plastic pipes (not shown) the ends of the pipes are each inserted in the respective ends of the fitting 10. The diameter of the bore of the fitting 10 is chosen so as to be a friction fit with the pipes which it is to connect. Once the pipes are in position an electrical current is made to flow through the copper wire 12 by appropriately connecting the ends 12 a, 12 b of the coil to a voltage source. The passage of electrical current through the wire 12 causes the wire to become heated which heat causes the plastic material surrounding the wire 12 to melt. In addition, the heat of the wire at least partially melts the outer surfaces of the pipes. After a predetermined time the current flow in the wire 12 is stopped and the pipes and the fitting are allowed to cool. The result is a welding together of each pipe to the fitting 10 to produce a relatively strong joint. Importantly, the joint is a gas-impermeable seal and so the fitting 10 can be used to sealably connect gas pipes.

Turning now to FIGS. 3 to 7, these show an apparatus for laying the wire 12 in a hollow cylindrical body such as a pipe fitting 10 as shown in FIGS. 1 and 2. Referring to FIG. 3, the wire-laying apparatus of the 10 first embodiment comprises a steel head portion 22, and a steel support arm 21 which is connected to and supports the head portion 22.

Mounted on the head portion 22 is a wirelaying tool 30 and a wire supply means including a guide pulley 23 which supplies the copper wire 12 to the wirelaying tool 30 during the wire-laying process. The head portion 22 has an arcuate friction surface which has been flame-hardened and polished. The head portion may also carry reaming cutter (not shown), such as in a position opposite to said wirelaying tool 30.

In use, a pipe fitting 10 is mounted, for example, on the spindle of a computer-numerically-controlled CNC machine (not shown) and the support arm 21 of the wire laying apparatus 20 is mounted in the tool-holder of the machine.

Optionally, a boring operation is first performed on 30 the fitting 10, using a separate boring (reaming) cutter, or conveniently using a boring cutter carried on the head portion 22 of the wirelaying tool 20.

The CNC machine is suitably programmed to rotate the fitting 10 at a first speed of up to about 2000 revolutions per minute, and to advance the wire-laying apparatus into the bore of the fitting 10 without initially making contact with the fitting 10.

Once the wire-laying apparatus is positioned fully inside the rotating fitting 10, at the end at which the fitting is secured to the spindle, the wire-laying apparatus is manoeuvred so that the boring cutter is made to cut into the inside bore-surface 11 of the fitting 10, to a predetermined depth, and the wire-laying apparatus is slowly withdrawn from inside the bore of the fitting at a predetermined rate, maintaining the cutting of the bore-surface at the predetermined depth, to perform a boring operation. This ensures that the bore-surface is consistently even and is smoothly cylindrical for the wire-laying operation.

Once the head portion 22 is fully withdrawn and any swarf or waste material has been removed, the CNC machine causes the head portion 22 to re-enter the bore of the fitting 10.

The wire-laying operation will now be described in general terms with reference to FIG. 3, and with reference to FIGS. 4 to 7 which show in more detail the wirelaying tool 30 of the wirelaying apparatus 20.

Skilled persons in the field of CNC machines will be familiar with the conventional descriptions of X, Y and Z movements as will be referred to below, with Y designating movement due to rotation of a workpiece relative to a tool, X designating movement in a horizontal plane normal to the axis of rotation of the workpiece, and Z designating movement parallel to the axis of rotation.

For the wirelaying process, the CNC machine causes the fitting 10 to rotate at approximately 50 revolutions per minute and the wirelaying tool 30 is brought into contact with the bore-surface 11 of the fitting 10 to cut a groove therein. The groove is substantially normal to the bore-surface 11 of the fitting 10. By moving the tool 30 at a constant rate in the direction of Z movement as represented by the arrow Z in FIG. 3, combined with constant rotational Y movement of the pipe fitting represented by the arrow Y in FIG. 4, a helical groove of constant pitch is formed.

Referring to FIG. 4, the preferred position of the tool 30 is shown relative to a pipe fitting 10, with the cutter 31 engaging the interior bore-surface 11. A flap closer 33 is arranged to lie on a plane normal to the axis of rotation of the fitting A, i.e. on the centre line of the fitting, and the cutter lies just above this centre line. Therefore, if the fitting 10 is exchanged for one of a larger diameter, the flap closer still lies close adjacent the bore surface 11. The same tool can be used to lay wire in pipes of different diameters.

As the cutter 31 of the tool 30 cuts a groove in the rotating bore-surface 11 of the fitting 10, a flange of plastics material is displaced to one side of the cutter 31. The wire 12 is fed through a feed aperture 32 in the cutter 31 directly into the freshly cut groove.

The flange of displaced plastics material is guided in a direction substantially parallel to the direction of cutting, to meet a flap closer surface 33 which extends across the tool 30 at an angle of approximately 45°. The flap closer 33 urges the flange towards the opposite side of the freshly cut groove to thereby at least partly cover the laid wire. The flap closer 33 then presses against the displaced material causing it to become heated due to friction. The result is that the displaced material is made to deform and enclose the wire in the cut groove.

The boring of the bore-surface 11, immediately prior to the wire-laying operation, provides the benefit that the bore-surface is still warm from friction caused by the boring cutter when the wire-laying process begins. This assists the further frictional heating of the bore-surface 11 by the flap closer 33 and by a friction surface of the head portion 22 as it causes the displaced plastic material to flow over the wire, thereby embedding the wire in the freshly cut groove.

The continuous process of the wirelaying therefore involves the temporary opening of a groove, the laying of wire in the groove, and the immediate enclosing of the wire in the groove.

Referring to FIGS. 5, 6 and 7, the wirelaying tool will now be described in more detail.

The wirelaying tool 30 is preferably formed by machining a single block of material such as steel to form a cutter 31, a wire guide aperture 32, and a flap closer 33. The wire guide aperture 32 extends from a wide oval shaped opening 32 a at the top and rear of the tool 30 at an angle in the range of about 20° to 30° to emerge at an opening 32 b in a face of the cutter 31 at the front of the tool.

The cutter 31 is provided with a first angled face 31 a leading to a cutting edge, and a second angled face 31 b for directing the wire exiting opening 32 b toward a desired area of the cut, preferably a strongest corner portion. The cutter 31 is narrower in the region of the first face 31 a than at the second face 31 b in order to progressively force the cut open.

It will be appreciated that modifications may be made 15 to the apparatus and method without departing from the scope of the invention. For example a CNC machine need not be used to operate the wire-laying apparatus, although it has been found convenient to do so. In addition, the laying of the wire could begin at the end of the fitting 10 closest to the spindle of the machine, with the head portion 14 gradually progressing out of the bore of the fitting 10.

The operation of the wirelaying apparatus to lay wire 25 in a pipe fitting having a variable internal diameter will now be described.

FIG. 8 is a sectional side view of a pipe fitting in the form of a reducer having a first end 14 for receiving a pipe of a first diameter, a second end 16 for receiving a pipe of a second, smaller diameter, and a sloping section 15 therebetween. It is desired to lay a continuous strand of wire from an inlet port 13 a to an outlet port 13 b. Previously this has not been possible because of the difficulty in correctly laying wire into the sloping section 15.

In operation, the wirelaying tool 31 is carried on the bar 21 into the first end 14 of the fitting and aligned with the first port 13 a. The bar 21 is then subject to an X axis move to drive the cutter 31 a predetermined depth into the interior bore surface 11. Next, the pipe fitting is rotated in the direction of arrow Y of FIG. 8, and the tool driven along direction Z to lay wire in a helical coil in a helical groove 124 of a first predetermined pitch. The first coil 124 is laid for a predetermined distance in order to achieve a reliable gas-tight joint in use. The coil does not continue along the entire length of the first section 14 of the pipe fitting 10 because the end portion of a pipe introduced into the first section 14 is particularly vulnerable to over heating, causing unwanted deformation. Therefore, a cold zone is provided by substantially increasing the rate of movement in the Z direction to provide a second helical coil 125, having a relatively large pitch. Once the tool advances to a desired region of the second, smaller, section 16 of the pipe fitting 10, the drive in the Z direction is slowed to provide a third helical coil 126 in the smaller diameter section 16.

As the tool enters the sloping portion 15, an X-direction move is required, i.e. out of the plane of the paper of FIG. 8, in order to follow the reducing diameter of the sloping section. Referring again to FIG. 3, it will be seen that the tool 30 is mounted in a recess at the forward end of the head portion 22 of the bar 21, such that the tool 30 is the first part of the wirelaying apparatus to encounter the sloping surface 15, and therefore the cutter 31 maintains contact with the interior bore surface 11 throughout the sloping section 15. Since the wire 12 enters the cut directly through the aperture 32 b in the cutter 31, the wire is reliably laid in the cut and does not run free inside the fitting.

A similar method of operation is used to lay a single 10 piece of wire in a pipe fitting having a non-usable area, such as a T-shaped pipe fitting having a side aperture positioned approximately half way along the length of the pipe fitting. Similar to the arrangement shown in FIG. 8, helical coils 124 and 126 are provided at either end of a T-shaped fitting, and a very large pitch helical coil 125 is used to avoid the side aperture by running the groove in the interior bore surface surrounding and opposite the aperture.

A second preferred embodiment of the wirelaying apparatus will now be described with reference to FIGS. 9 to 13, where like reference numerals are used for parts corresponding to the apparatus described with reference to FIGS. 1 to 8.

FIG. 9 shows a rear elevational view of the wirelaying apparatus 20 having a support arm 21 carrying a head portion 22. In use, wire to be laid is carried along the support arm 21 such as by a pulley arrangement (not shown) to an aperture 23.

FIG. 10 is a plan view of the apparatus of FIG. 9, showing the aperture 23 passing through the head portion 22 from an entry 23 a to an exit 23 b.

FIG. 11 is a end view of the apparatus FIGS. 9 and 10, and FIG. 12 is a sectional view through the head portion 22.

As shown more clearly in FIGS. 11 and 12, the head 10 portion 22 is provided with a curved forward facing pressure or friction surface 24 intended to lie in use against the interior bore surface 11 of a pipe fitting, as in the first embodiment.

A hollow shaft 25 is provided in the aperture 23 having a splined end 25 a which acts as a pinion arranged to be engaged with a rack 26 carried on the support arm 21. Longitudinal movement of the rack 26 rotates the hollow shaft 25 within the aperture 23.

A cutter 31 is provided at a forward end of the shaft protruding from the exit 23 b of aperture 23. The cutter 31 is preferably non-rotatably received within the interior end 25 b of the shaft 25, to rotate with the shaft 25, such 25 as a square cross-section fitting into a corresponding square recess. The rack 26 and pinion 25 a arrangement is conveniently sized so as to fit within the confines of the support arm 21 and head 22 and thus fit within a pipe fitting, but any other suitable rotation arrangement may be employed.

In use, a wire 12 to be laid is guided through the hollow centre of the shaft 25, conveniently using a ceramic disc 27 at the entry thereof to reduce friction. The wire 12 passes through the central longitudinal wire guide aperture 32 of cutter 31, to emerge from the cutter 31 directly into the freshly cut groove. Conveniently, the cutter 31 may be rotated about the wire 12, such that the wire may be laid in a groove which changes direction whilst the cutter 31 is engaged in the bore surface 11 of the fitting 10.

The exit 23 b of the aperture 23 is provided with a plate 28 having a plurality of flap closers 33 mounted thereon or formed therein. The or each flap closer 33 is arranged to lie rearwardly in the direction of cutting from the cutter 31.

Referring now to FIG. 13, a preferred method of operation of the apparatus shown in FIGS. 9–2 will now be described.

FIG. 13 shows a section of a pipe fitting 10 where it is desired to lay a single continuous piece of wire 12 in a double helical path from an input port 13 a to an output port 13 b. This arrangement finds particular application, for example, when it is desired to provide more than one coil arrangement in a pipe fitting so that joints may be made separately, conveniently at different points in time. The double helical coil arrangement may be used with any form of pipe fitting, including a sleeve, reducer, T-shaped, elbow or cap-end pipe fitting.

With reference in particular to FIG. 12 and FIG. 13, the cutter 31 is set to a first direction and driven by suitable X and Z movement of the support arm 21 through the interior bore surface 11 of the pipe fitting 10 which is rotated past the cutter 31, such that wire 12 is laid in a first inward helical coil 121.

At the end of the first helical coil 121, the rotation of the fitting 10 and the movement of the head 22 and arm 21 is stopped. That is, at position 121 a of FIG. 13. The cutter 31 is then rotated by means of the rack 26 and the pinion 25 a through about 90° to a second desired cutting direction. The wire 12 is laid in the second direction in a linear path without the fitting 10 being rotated, to form a connecting portion 122. The connecting portion is ideally of a length corresponding to one half of the pitch of the first helical coil 121. The tool 31 is then rotated again to a third cutting direction, preferably through about 90° such that the tool has rotated through about 180° from the first cutting direction. By rotating the fitting 10 in the reverse direction and performing a movement in the reverse Z direction of the head portion 22, the cutter 31 scribes a second helical path 123 from the position 123 a to the outlet port 13 b.

FIGS. 14, 15 & 16 show another preferred embodiment of the wirelaying tool according to the present invention. The wirelaying tool 30 is machined to form a cutting tip 31, a wire guide aperture 32, and a flap closer 33, similar to the embodiment shown above in FIGS. 5, 6 & 7.

As shown in FIGS. 14, 15 & 16, in this alternate 30 embodiment the cutting tip 31 has two symmetrical cutting faces 31 a′ and 31 a″, which plough a symmetrical furrow in the interior bore surface and displace material to either side of the cutting tip. This arrangement has been found to provide a clean and reliable cut. Wire is laid into the opened cut through the wire guide aperture 32. The wire exits the cutting tip 31 at exit aperture 32 b, directly into the open cut. The flap closer 33 then urges the flanges of displaced material back into the interior bore surface to close the cut. Any excess material remaining at the surface is conveniently trimmed in a separate reaming operation after wirelaying has been completed. In this embodiment, the flap closer 33 is perpendicular to the direction of travel of the cutting tool, which allows excess material to travel along the flap closer 33 away from the cutting tip 31, and avoids build-up. The combination of the symmetrical cutting tip 31 and the perpendicular flap closer 33 gives a superior smooth finish to the pipe fitting after the wirelaying operation. This arrangement is ideally suited for use with coupler, T and elbow type pipe fittings. In yet another embodiment (not shown) the cutting tip is offset to one side of the tool. The cutting tip then better follows a sloped interior bore surface and is ideally suited to reducer type pipe fittings.

FIG. 17 is a perspective view to further illustrate the preferred wirelaying tool in use. FIG. 18 is an 25 enlarged view of a selected part of FIG. 17. FIG. 19 illustrates the preferred wirelaying tool in use whilst laying wire into a cut.

FIGS. 17, 18 & 19 show that the wire 12 exits the 30 cutting tip 31 directly into the cut opened by the cutting tip. Ideally, the wire is laid into the hollow cylinder 10 such as a pipe fitting and is placed below the interior bore surface 11.

As illustrated herein, the wirelaying tool 30 is ideally arranged to be readily replaceable. That is, the tool 30 is a wearing component and can be replaced frequently if needed, by fitting a new tool 30 to the recess of the cutting head 22, as shown in FIG. 3. Hence the wirelaying tool is quickly and easily replaced, with minimal downtime.

In particular, extensive adjustment and recalibration of the wirelaying system is not required. Further, different tools can be swapped to do different jobs, such as working with pipe fittings of different diameters. The preferred replaceable wirelaying tool is simple to work with and has many practical benefits.

The present invention extends to cover the embodiments of the wirelaying apparatus and the methods of operation of the wirelaying apparatus, as described above, and the pipe fittings produced by said apparatus and methods. The invention extends in particular to the wirelaying tool 30 having a wire guide aperture therethrough for delivering wire directly in to the cut.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. 

1. A wirelaying tool for laying wire into an interior bore surface of a hollow cylinder, comprising: a cutting tip to, in use, make a cut into an interior bore surface of a hollow cylinder; a wire guide aperture to guide a wire into the cut, the wire guide aperture extending through the cutting tip to an exterior surface of the cutting tip lying in the cut in use such that the wire enters the cut directly through the culling tip; and an encloser to close the cut after the wire has been fed into the cut, thereby enclosing the wire in the cut.
 2. The wirelaying tool of claim 1, wherein the wirelaying tool is adapted to be carried on an elongate bar having a wire delivery unit for delivering wire to the wire guide aperture.
 3. The wirelaying tool of claim 1, wherein the wirelaying tool is arranged to be readily releasably coupled to a head portion of an elongate bar.
 4. The wirelaying tool of claim 3, wherein the wirelaying tool is arranged to be carried in a recess of the head portion.
 5. The wirelaying tool of claim 4, wherein the wirelaying tool is mountable into a receiving recess of the elongate bar such that the wirelaying tool is carried aligned with an end face of the head portion and aligned with or protruding from an outer circumferential face of the head portion.
 6. The wirelaying tool of claim 1, wherein the encloser is operatively arranged to lie in a plane normal to the longitudinal rotational axis of the hollow cylinder having the interior bore surface.
 7. The wirelaying tool of claim 1, wherein the cutting tip, the wire guide aperture and the encloser are integrally formed.
 8. The wirelaying tool of claim 1, wherein the cutting tip is arranged to produce the cut by lifting at least one flange of material from the interior bore surface, and wherein the wire guide aperture guides the wire into the cut to an area underneath the at least one flange.
 9. The wirelaying tool of claim 1, wherein the cutting tip is arranged to divide the interior bore surface either side of the cutting tip, thereby making a cut into the interior bore surface.
 10. A wirelaying apparatus for laying wire into an interior bore surface of a hollow cylinder, comprising: an elongate bar; a head portion carried by the elongate bar; a wirelaying tool adapted to be readily releasably coupled to the head portion, and in use carried by the head portion, wherein the wirelaying tool comprises: a cutting tip for making a cut into an interior bore surface of a hollow cylinder; a wire guide aperture for guiding wire into the cut, the wire guide aperture extending through the cutting tip and lying in the cut in use such that the wire enters the cut directly through the cutting tip; and an encloser for closing the cut after the wire has been fed into the cut, thereby enclosing the wire in the cut.
 11. The wirelaying apparatus of claim 10, further comprising: a wire delivery unit for delivering wire along the 20 elongate bar to the head portion and into the wire guide aperture of the cutting tip.
 12. The wirelaying apparatus of claim 10, wherein the head portion carries a reaming cutter for reaming the interior bore surface of the hollow cylinder.
 13. A method for laying wire into an interior bore surface of a hollow cylinder, comprising the steps of: opening a cut in the interior bore surface using a cutting tool having a cutting tip; guiding a wire directly into the cut by means of a wire guide aperture extending through the cutting tip to an exterior surface thereof lying in the cut; and closing the cut to enclose the wire in the cut.
 14. The method of claim 13, further comprising the step of reaming the interior bore surface prior to forming the cut.
 15. The method of claim 13, comprising: rotating the hollow cylinder relative to the cutting tool, thereby opening the cut in the interior bore surface using the cutting tip; and progressively feeding the wire into the cut directly through the cutting tip, so that the wire exits the wire guide aperture below an existing surface level of the interior bore surface of the hollow cylinder.
 16. The method of claim 13, comprising continuously laying wire into the interior bore surface of a reducer pipe fitting, including laying wire in one progressive action in each of a first section for receiving a pipe of a first diameter, a second section for receiving a pipe of a second larger or smaller diameter, and a sloping section therebetween.
 17. The method of claim 16, comprising the steps of laying wire in a first helical coil in the first section, laying a second helical coil having a relatively large pitch in the sloping section, and laying a third helical coil in the second section.
 18. The method of claim 13, comprising laying wire at a first end of a T pipe fitting, laying wire in a large pitch helical coil sufficient to avoid a side aperture in the interior bore surface of the T pipe fitting, and laying wire in a second end of the T pipe fitting, all in one continuous action. 